1. Field of the Invention
The present invention relates to a housing frame of an electrical apparatus.
2. Description of the Related Art
A large-sized electrical apparatus, such as a power converter, houses semiconductor devices, capacitors, connection conductors, and so on inside the housing. The housing is constituted by a frame including a plurality of beams and an outer wall consisting of a plurality of panels (refer to, e.g., Patent Document 1: Jpn. Pat. Appln. Laid-Open Publication No. 2008-84981, the entire content of which is incorporated by reference). Typically, the beam is formed of an equal angle steel (or an equal angle bar), a steel bar having an L-shaped cross section. The frame is formed by welding a plurality of equal angle steels.
The equal angle steel used to constitute the abovementioned conventional housing frame is standardized in terms of the dimension, shape, and the like. Thus, in order to obtain a housing frame of an electrical apparatus having an arbitrary dimension and shape, large amount of cost and effort are required. Further, since the conventional housing frame is formed by welding a plurality of equal angle steel, higher level of skill is required for an operator in order to obtain a housing frame having a high dimensional accuracy.